Shane Peterson to make major-league debut with A’s tonight — called it ‘everybody’s dream’

Last time Peterson hooked up with the A’s, it was in Houston, and he was insurance in case Brandon Moss was put on paternity leave. Didn’t happen, so Peterson returned to Triple-A Sacramento.

Well, Moss was placed on the paternity list today, and Peterson was added to the roster. Plus he’s in the lineup – at first base and hitting eighth.

“I’d never been to this stadium before. . . . It’s nice being home,” Peterson said before the game.

Lot of emotions for the 25-year-old who was acquired from the Cardinals in the 2009 Matt Holliday trade. He’s from Temecula, and his folks, Brad and Sue, are making the 7-hour trek today. They flew from Sacramento to Houston when it appeared their son would make his big-league debut last time. So they’re making the rounds.

“Obviously it’s been worth it for them,” Peterson said.

Bob Melvin said Peterson’s natural position is first base. He played there just once in his 11 games at Sacramento, and that was Monday. He was hitting .410 with an eye-opening .558 on-base percentage, thanks to a league-high 13 walks. In his last six games, he hit .519, 14 hits in 29 at-bats.

It was a carryover from spring training when he hit .408.

“This is everybody’s dream,” Peterson said. “If it would have taken me 500 games, five games, 5,000 games, whatever it is, it means a lot to be here and get this opportunity. Who knows how long it’s going to be, but that’s something I try not to worry about.”

Meantime, the A’s were waiting word on Moss’ wife, Allison. Melvin said the plan was for Moss to miss two games and join the team flight to Florida on Thursday.

—— In other news, Scott Sizemore had his ACL surgery in Pensacola, Fla., with Dr. James Andrews performing the operation. The reconstruction was made possible with a patellar tendon graft. In last year’s ACL procedure, a tendon from Sizemore’s hamstring was used.

He’ll return to the Bay Area for rehab on Saturday.

—— Adam Rosales is tentatively slated to begin his rehab assignment Wednesday. Early today, he made several throws across his body from second base and turned double plays, showing he was recovered from his strained left intercostal.

—— Hiro Nakajima isn’t close to a rehab assignment. Melvin said the infielder (strained left hamstring) might begin the assignment when the A’s return for their next homsteand, which begins April 25. Nakajima’s next step is to run the bases this weekend.